letter to court for a friend

my friend lost his spanish wife 2 years ago from an illness that could have been avoided if the hospital had dealt with it more promptly. The case has been taken to court and now the hospital concerned are saying that my friends wife didnt understand english and couldnt speak english very good and this is why the illness wasnt taken as serious as it should have been. I knew my friends wife very well and there was nothing wrong with her understanding and speaking the english language. I need to put this in writing for my friend as evidence for his court case. Can you help me with this please.